Anatomical Differences Determine Distribution of Adenovirus after Convection-Enhanced Delivery to the Rat Brain

Background: Convection-enhanced delivery (CED) of adenoviruses offers the potential of widespread virus distribution in the brain. In CED, the volume of distribution (Vd) should be related to the volume of infusion (Vi) and not to dose, but when using adenoviruses contrasting results have been reported. As the characteristics of the infused tissue can affect convective delivery, this study was performed to determine the effects of the gray and white matter on CED of adenoviruses and similar sized super paramagnetic iron oxide nanoparticles (SPIO). Methodology/Principal Findings: We convected AdGFP, an adenovirus vector expressing Green Fluorescent Protein, a virus sized SPIO or trypan blue in the gray and white matter of the striatum and external capsule of Wistar rats and towards orthotopic infiltrative brain tumors. The resulting Vds were compared to Vi and transgene expression to SPIO distribution. Results show that in the striatum Vd is not determined by the Vi but by the infused virus dose, suggesting diffusion, active transport or receptor saturation rather than convection. Distribution of virus and SPIO in the white matter is partly volume dependent, which is probably caused by preferential fluid pathways from the external capsule to the surrounding gray matter, as demonstrated by co-infusing trypan blue. Distant tumors were reached using the white matter tracts but tumor penetration was limited. Conclusions/Significance: CED of adenoviruses in the rat brain and towards infiltrative tumors is feasible when regional anatomical differences are taken into account while SPIO infusion could be considered to validate proper catheter positioning and predict adenoviral distribution

Gene therapy for monogenic liver diseases: clinical successes, current challenges and future prospects

Over the last decade, pioneering liver-directed gene therapy trials for haemophilia B have achieved sustained clinical improvement after a single systemic injection of adeno-associated virus (AAV) derived vectors encoding the human factor IX cDNA. These trials demonstrate the potential of AAV technology to provide long-lasting clinical benefit in the treatment of monogenic liver disorders. Indeed, with more than ten ongoing or planned clinical trials for haemophilia A and B and dozens of trials planned for other inherited genetic/metabolic liver diseases, clinical translation is expanding rapidly. Gene therapy is likely to become an option for routine care of a subset of severe inherited genetic/metabolic liver diseases in the relatively near term. In this review, we aim to summarise the milestones in the development of gene therapy, present the different vector tools and their clinical applications for liver-directed gene therapy. AAV-derived vectors are emerging as the leading candidates for clinical translation of gene delivery to the liver. Therefore, we focus on clinical applications of AAV vectors in providing the most recent update on clinical outcomes of completed and ongoing gene therapy trials and comment on the current challenges that the field is facing for large-scale clinical translation. There is clearly an urgent need for more efficient therapies in many severe monogenic liver disorders, which will require careful risk-benefit analysis for each indication, especially in paediatrics

Gene Therapy-Mediated Reprogramming Tumor Infiltrating T Cells Using IL-2 and Inhibiting NF-κB Signaling Improves the Efficacy of Immunotherapy in a Brain Cancer Model

Immune-mediated gene therapy using adenovirus expressing Flt3 ligand and thymidine kinase followed by ganciclovir administration (Flt3/TK) effectively elicits tumor regression in preclinical glioma models. Herein, we assessed new strategies to optimize Flt3L/TK therapeutic efficacy in a refractory RG2 orthotopic glioblastoma model. Specifically, we aimed to optimize the therapeutic efficacy of Flt3L/TK treatment in the RG2 model by overexpressing the following genes within the brain tumor microenvironment: 1) a TK mutant with enhanced cytotoxicity (SR39 mutant TK), 2) Flt3L-IgG fusion protein that has a longer half-life, 3) CD40L to stimulate DC maturation, 4) T helper cell type 1 polarizing dendritic cell cytokines interleukin-12 or C-X-C motif ligand 10 chemokine (CXCL)-10, 5) C-C motif ligand 2 chemokine (CCL2) or C-C motif ligand 3 chemokine (CCL3) to enhance dendritic cell recruitment into the tumor microenvironment, 6) T helper cell type 1 cytokines interferon-γ or interleukin-2 to enhance effector T-cell functions, and 7) IκBα or p65RHD (nuclear factor kappa-B [NF-κB] inhibitors) to suppress the function of Foxp3+ Tregs and enhanced effector T-cell functions. Anti-tumor immunity and tumor specific effector T-cell functions were assessed by cytotoxic T lymphocyte assay and intracellular IFN-γ staining. Our data showed that overexpression of interferon-γ or interleukin-2, or inhibition of the nuclear factor kappa-B within the tumor microenvironment, enhanced cytotoxic T lymphocyte-mediated immune responses and successfully extended the median survival of rats bearing intracranial RG2 when combined with Flt3L/TK. These findings indicate that enhancement of T-cell functions constitutes a critical therapeutic target to overcome immune evasion and enhance therapeutic efficacy for brain cancer. In addition, our study provides novel targets to be used in combination with immune-therapeutic strategies for glioblastoma, which are currently being tested in the clinic.Fil: Mineharu, Yohei. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Muhammad, AKM Ghulam. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Yagiz, Kader. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Candolfi, Marianela. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kroeger, Kurt M.. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Xiong, Weidong. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Puntel, Mariana. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Liu, Chunyan. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Levy, Eva. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Lugo, Claudia. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Kocharian, Adrina. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados UnidosFil: Allison, James P.. Howard Hughes Medical Institute; Estados UnidosFil: Curran, Michael A.. Howard Hughes Medical Institute; Estados UnidosFil: Lowenstein, Pedro R.. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados Unidos. University of Michigan; Estados UnidosFil: Castro, Maria G.. Cedars Sinai Medical Center. Gene Therapeutics Research Institute; Estados Unidos. University of California at Los Angeles; Estados Unidos. University of Michigan; Estados Unido